The GH1 is still king as it offers 720p60 which is far more useful than stuttery old 24p that can't capture motion. Moreover, the D90 rolling shutter makes the camera unusable for anything but a demo clip.

Plus Panasonic has solved AF noise issue with a lens for video. It also supports AF during zooms.

Canon will not be the "champ" because it's 2X more expensive and so in a completely different price range. It's not an apples to apples comparison. Moreover, the VF doesn't work when shooting video making it unuseable outdoors during the day -- just like the D90.

Only the GH1 has been built for HD video on top of a shipping still camera.

Moreover, the D90 rolling shutter makes the camera unusable for anything but a demo clip.

Agreed. Nikon could have improved this substantially with video crop modes that use a smaller portion of the sensor. This would also reduce the image downsampling artifacts and possibly allow for higher frame rates.

if a smaller potion of the sensor was used would this not effectively be taking away the main advantage these cameras have over regular video cameras? ie. lowlight shallow dof etc. by allowing more light fall on a larger area. Isn't the whole buzz about this related to the fact that its a sensor similar in size to a 35mm film/dv pro camera?
Im not stating this as fact, merely asking if its the case or not. If those things are all down to the lens then fair point.

Ive seen some good stuff produced with the d90 in recent times. Rolling shutter is a nightmare but it can be worked around.